Vapor rectifier



Feb. 25, 1930. KERN 1,748,133

VAPOR RECTIFIER Filed July 2, 1925' WWW/WWW- W k 0' 0 i i 1 I WI 7 W2IWA' A /m I A L": 2% r 5 0 H- -H-- T:::::} \K

Inventor Erwin Kerp Attorney Patented Feb. 25, 1930 UNITED STATES PATENTorricn ERWIN, KERN, OF WETTIN GEN, NEAR BADEN, SWITZERLAND, ASSIGNOR TQAKTTEN- GESELLSCI-IAFT BROWN BOVERI & CIR, F BADEN, SWITZERLAND VAPORRECTIFIER Application. filed July 2, 1925, Serial N'o.

Vapor rectifiers constructed of metal are frequently subject totransitory andquite. short-lived flashing over which is generallyterminated by the sudden cutting out of the are in the defective phase.Such sudden interruptions in the Current cause an excess of potential inthe inductances of the anode circuit with tl1e-resultthat the insulationof the rectifier installation is subjected to great stress and may beeasily damaged. If, in

addition, sparking occurs from anode to anode a further flashing over ofa more violent nature may be started. It is important therefore toprovide means for preventing sparking from anode to anode by limitingthe excess of potential to an amount that involves no risk. Exhaustiveexperiments have shown that when excess of potential occurs the metalcontainer of the rectifier always assumes the potential of the normallyworking anodes, whilst the defective anode, i. e., the anode which hasbeen acting as a cathode during the transitory flashing back,

shows a high potential as compared with the metal container. 1

This invention consists of means for preventing excessive potentialdifferences as between electrodes in vapor rectifiers constructed ofmetal, and in accordance therewithseveral paths for the current areprovided between the circuits of the several electrodes and the metalcontainer of the rectifier, such paths containing spark gaps and ohmicresistances. The spark. gaps are preferably adjusted for an excess ofpotential which is less than the value of the potential permissible forthe insulation of the installation. The effect of this arrangement isthat no dangerous excess potential dilierence can occur since evenaslight rise will cause a spark discharge between the circuit of the41,128, and in Germany August 8, 1924.

ing the halves Q} and Q The outer terminal of the winding Q is connectedto the anode A and the outer terminal of the winding Q to the anode A Drepresents the cooling dome and K the cathode of the -rectifier. Theload V is connected between the cathode K and the common terminal of thewindings Q and Q The anode A is connected through the resistance VW andthe spark gap F to the metal container Gr. Similarly, the anode A isconnected through the resistance and the spark gap F to the metalcontainer G, and the cathode K is connected through the resistance andthe spark gap F to the metal container G. With this arrangement it isimmaterial which of the electrodes assumes a high potential, since therewill always be a sufficiently early discharge to the metal container toprevent its reaching a point of danger. Thus the limit for the potentialwhich an electrode may reach can be fixed beforehand by the adjustmentof the I spark gap.

This arrangement can be used also with advantage in the case ofpolyphase rectifiers.

What I claim is 1. In vapor apparatus for rectifying alternatingcurrent, an insulated metal container, electrodes disposed in said metalcontainer and insulated therefrom, and a spark gap and an ohmicresistance connected be tween each electrode and the metal container.

2.'In a system for rectifying alternating current, an alternatingcurrent supply, a metal vapor rectifier comprising a metal container andelectrodes disposed in the latter and insulated therefrom, transformermeans connecting said rectifier to said supply in rectifying relationwith respect thereto,

and means responsive to conditions tending to produce a predeterminedpotential difference between certain of said electrodes and beingoperable at substantially such conditions to provide anelectrostaticdischarge circuit between the electrode of higher potential and saidcontainer.

3. In a system for rectifying alternating I current, an alternatingcurrent supply, a

container and electrodes disposed in the latter and insulated therefrom,transformer means Connecting said rectifier to said supply in rectifyingrelation with respect thereto, and means responsive to conditionstending to produce a predetermined potential differ.- ence betweencertain of said electrodes and being operable atsubstantially suchconditions to provide an electrostatic discharge circuit between theelectrode of higher potential and said container said last-named meansincluding a discharge gap and a resistance in series therewith.

4:. In apparatus of the sort described, the combination with therectifier casing, anodes and anode supply windings, of a spark gap andohmic resistance providing an excessvoltage shunt between the casingandsupply windings. A

. 5. In apparatus of the sort described, the combination with therectifier casing and electrodes, of a spark gap and ohmicresistanceproviding an excess-voltage shunt between the casing and electrodes. 7

6. In apparatus of the sortdescribed, the

combination with the rectifier casing and electrodes, of a spark gap andohmic resistance providing an excess-Voltage shunt between the casingand respective electrodes.

Dated this 16th day of June, 1925.

- ERWIN KER-N.

